:root {
  --bg: #0b1320;
  --panel: #111c2b;
  --card: #182437;
  --border: rgba(255,255,255,.14);
  --text: #edf4ff;
  --muted: #9fb0c8;
  --accent: #7cf0bd;
  --accent2: #ffe07a;
  font-family: "IBM Plex Sans", "Segoe UI", sans-serif;
}
*{box-sizing:border-box}
body{
  margin:0;
  min-height:100vh;
  color:var(--text);
  background:
    radial-gradient(circle at top left, rgba(124,240,189,.16), transparent 30%),
    linear-gradient(180deg, #0b1320, #132236);
}
.page{max-width:1080px;margin:0 auto;padding:24px 16px 48px}
.hero,.card{
  background:var(--panel);
  border:1px solid var(--border);
  border-radius:24px;
  box-shadow:0 24px 60px rgba(0,0,0,.28)
}
.hero{padding:24px}
.hero h1{margin:0 0 8px;font-size:clamp(2rem,5vw,3rem)}
.hero p{margin:0;color:var(--muted)}
.toolbar,.question{margin-top:20px;padding:20px}
.tabs,.actions{display:flex;gap:10px;flex-wrap:wrap}
button,input{font:inherit}
.tab,.secondary,.option{
  border:1px solid var(--border);
  background:rgba(255,255,255,.03);
  color:var(--text)
}
.tab,.secondary,.primary,.option{border-radius:16px;padding:12px 16px}
.tab.active{background:rgba(124,240,189,.12);border-color:var(--accent)}
.search{
  width:100%;
  background:rgba(255,255,255,.03);
  border:1px solid var(--border);
  border-radius:16px;
  color:var(--text);
  padding:14px 16px;
  margin-top:8px
}
.primary{background:linear-gradient(120deg,var(--accent),var(--accent2));color:#18222a;border:none;font-weight:700}
.meta{display:flex;justify-content:space-between;gap:16px;color:var(--muted)}
.prompt{font-size:1.2rem;line-height:1.6;margin:20px 0}
.options{display:grid;gap:12px}
.option{text-align:left;cursor:pointer}
.option.selected{border-color:#7db8ff;background:rgba(125,184,255,.12)}
.option.correct{border-color:var(--accent);background:rgba(124,240,189,.12)}
.option.wrong{border-color:#ff93a6;background:rgba(255,147,166,.12)}
.label{display:inline-flex;width:28px;font-weight:700;color:var(--accent)}
.answer{
  margin-top:18px;
  padding:16px;
  border-radius:18px;
  border:1px solid rgba(124,240,189,.2);
  background:rgba(124,240,189,.07);
  white-space:pre-line
}
.hidden{display:none}
.helper{color:var(--muted);margin-top:10px}